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• ffmpeg configure always returns "not found" when using sysroot and cross-prefix options - how to use them correctly ?

  5 août 2014, par user2212461

  I try to build ffmpeg with a cross-compiler. When setting the configure flags I am getting the following errors :

  WARNING: Compiler does not indicate floating-point ABI, guessing soft.
  
  build_it.sh: 29: build_it.sh: --sysroot=/home/android/android-ndk-r9/platforms/
  
      android-9/arch-arm/: not found
  
  build_it.sh: 32: build_it.sh.sh: --cross-prefix=/home/android/android-ndk-r9/
  
      toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86/bin/arm-linux-and
  
      roideabi-: not found

  The error message "not found" sounds like the paths dont exist but they are all correct and existing. How can I resolve this error ?

  build_it.sh :

  NDK=/home/android/android-ndk-r9
  
  SYSROOT=$NDK/platforms/android-9/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86
  
  CPU=arm
  
  PREFIX=test
  
  ADDI_CFLAGS="-marm"
  
  platform="android-9"
  
  
  
  ./configure \
  
      --disable-asm \
  
      --enable-shared \
  
      --target-os=linux \
  
      --arch=arm \
  
      --enable-cross-compile \
  
      --disable-static \
  
      --sysroot=$SYSROOT \
  
      --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
  
      --extra-ldflags="$ADDI_LDFLAGS"
  
      --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
      --prefix=$PREFIX \
  
  
  
  ##configure fails here
  
  ...

• pyav - cannot save stream as mono

  3 août 2022, par Zvika

  I'm trying to use pyav to convert arbitrary audio file to a low quality, mono, wave file.

  


  I almost managed to do it, but it's stereo, and I couldn't find how to make it mono. Furthermore, I think I made some mistake here, as I had to repeat the rate in the output_container.add_stream and in the AudioResampler - it seems redundant, and I can't understand what would happen if those numbers won't match.

  


  My code is :

  


      import av
    
    input_file = 'some.mp3'
    output_file = 'new.wav'
    
    rate = 22000
    
    output_container = av.open(output_file, 'w')

    # can I tell `output_stream` to just use `resampler`'s info?
    # or, if not, how can I tell it to have only 1 channel?
    output_stream = output_container.add_stream('pcm_u8', rate)  
    
    resampler = av.audio.resampler.AudioResampler('u8p', 'mono', rate)
    
    input_container = av.open(input_file)
    for frame in input_container.decode(audio=0):
        out_frames = resampler.resample(frame)
        for out_frame in out_frames:
            for packet in output_stream.encode(out_frame):
                output_container.mux(packet)
    output_container.close()


  


  And not related to my main question, but any comments regarding my code, or pointing out mistakes, are welcomed. I hardly could find usage examples to use a reference, and PyAV API documentation isn't very detailed...

  


• ffmpeg save highly quality video by using rtsp link [closed]

  22 août 2023, par Shivam Singh

  I'm trying to download good quality of video from the camera stream by using ffmpeg

  


  ffmpeg -i rtsp://admin:admin@123@117.216.143.251:556 -r 15 /home/Documents/Yolo/yolo/251.avi


  


  How to download good quality of video by using ffmpeg ?